I've noticed the add here for Tam Valley's 5A DCC booster.  $42 sounds like a heck of a deal, but I'd like to hear the opinion of some others out there before jumping in.  Assuming that I provide a power supply, is that all I would need to run my layout (using a Zephyr as a command station and possibly yard booster)?  Has anybody used this booster, and can provide an opinion on quality, function, value, etc?

Here's the link, in case the Tam Valley ad isn't up at the moment:

Has anyone installed a decoder or sound decoder in a Bachmann Spectrum GP30? I have 2 about 10 years old with NO running time on them. I have searched the forum posts and looked at Alan Gartner's wiring for DCC web site. Alan Has some info but it is dated.

I would also like to install sound but am not sure there is space given the "frame" design. Any thoughts on where to put a speaker would be appreciated. 

I'm building a shelf-type urban industrial module (three  8' x 2' tables in an 18' x 8' L-shaped layout) and was wondering about how many control panels to place and where, or whether to use the fascia as one giant control panel, placing the switch toggles in front of the actual switch locations.

I have what is essentially a single track mainline with reverse loops at each end. The loop at one end is a long dogbone in which the two tracks run parallel for some distance to give the impression of a double track mainline. I assume I follow the directions for wiring reverse loops for this section but are there any issues with having a long loop section? Also, how does the wiring change if I add crossovers where the tracks run parallel? I am wiring for dcc.